Units for extracting the power from the wind have been known for centuries for driving mills, pumping water and the like. However these were very inefficient and had to be large in order to produce the required power.
Of recent years turbines have been developed in order to achieve greater efficiency from smaller units. Australian Pat. No. 513,247 discloses a wind turbine assembly having a rotor with a plurality of vanes in radially spaced relation to the axis, and flow controlling duct means to conduct a radial outflow of air against the vanes, the turbine having an aero-foil surface formed on an inlet duct, the vanes being situated in a low pressure area at the trailing edge of the aero-foil.
Australian Patent Application No. 213,391/77 discloses a turbine rotor having vanes mounted in a convergent-divergent duct, flow channels through the duct wall controlling the boundary layer.
Australian Pat. No. 492,087 shows a wind turbine having a duct in which is mounted stator and rotor blades.
It is an object of this invention to provide an improved wind turbine having advantages over the known art, in that it is more effective in converting the wind energy into motive power.
It is a further object to provide a wind turbine which is effective in delivering power from winds of low velocity.